Abstract 5465: Systematic interrogation of druggable pathways in pancreatic adenocarcinomas using pooled gene-knockdown lentiviral libraries

Abstract

Abstract Despite significant advances in the development of cancer treatment in the last 20 years the best available therapies have marginally improved the survival rate of treated pancreatic cancer patients (from 3% to 6% five-year survival), making it still one the deadliest malignancies. Single standard of care cytotoxic and targeted therapies demonstrate little to no effect on patient survival. Even though we now understand some of the main genetic factors that are mutatated in pancreatic tumors, their role in drug response remains poorly understood. To identify drug-sensitizing genetic targets in cancer cells we have developed a high-throughput screening platform. In this methodology, pooled lentiviral libraries containing hundreds of knockout constructs specific for cancer-related genes are used to infect cancer cells. By treating the infected populations with therapeutic agents we are able to identify genetic targets that when inhibited synergize with existing drugs to cause increased cell death. We piloted this type of screening platform in HCT-116 cells, a KRAS mutant, MEK inhibitor resistant colorectal cancer cell line, using the MEK-inhibitor AZD-2644 and a pooled shRNA library. This study identified 4-7 target genes that when knocked down sensitized the previously resistant HCT-116 cells to AZD-2644. To conduct a more robust and representative sensitization screen we developed a lentiviral CRISPR-Cas9 library. By performing screens in a panel of pancreatic cancer cell lines, we have identified both cell line dependencies and sensitizers to targeted and cytotoxic chemotherapies. The findings from these screens provide potential mechanistic insights into the key survival signaling programs in pancreatic cancer as well as new therapeutic strategies. Citation Format: Edgar Ferrer-Lorenzo, Daniel P. Nussbaum, Peter Winter, Kris Wood. Systematic interrogation of druggable pathways in pancreatic adenocarcinomas using pooled gene-knockdown lentiviral libraries. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5465. doi:10.1158/1538-7445.AM2015-5465